Apparatus for pumping materials



June 27, 1961 H. N. K. PATON 2,990,048

APPARATUS FOR PUMPING MATERIALS Filed April 22, 1959 5 Sheets-Sheet 1 mus/wok HAMILTON NEIL KING PATON June 27, 1961 PATON 2,990,048

APPARATUS FOR PUMPING MATERIALS Filed April 22, 1959 5 Sheets-Sheet 2 I05 75 I00 14 43 12 I02 50 49 -1 54 sz 33 r-ll INVENTOR HAMILTON NEIL KING PATON June 27, 1961 H. N. K. PATON 9 APPARATUS FOR PUMPING MATERIALS Filed April 22, 1959 5 Sheets-Sheet 3 INVFNTOR 'HAMILTON NEIL KING PATON June 27, 1961 H. N. K. PATON Filed April 22, 1959 APPARATUS FOR PUMPING MATERIALS 5 Sheets-Sheet 4 I24 I26) I00 I23 102 III;

I203 I ll Il'll II II I00 lli 5 I INVENTOR HAMILTON NEIL KING PATON June 27, 1961 H. N. K. PATON APPARATUS FOR PUMPING MATERIALS 5 Sheets-Sheet 5 mn-wrok HAMILTON NEIL KING PATON Filed April 22, 1959 States This invention relates to an apparatus for pumping materials in particle form, and particularly for feeding said materials continuously into high pressure zones which may be in the form of pneumatic conveying pipes, or chambers for directing these materials and air into conveying pipes.

An object of the present invention is the provision of apparatus for pumping materials in small particle form, such as flour, cement, sugar and wheat,'continuously into high pressure systems without blowback.

A further object is the provision of apparatus for moving small particle material into a high pressure zone by means of a succession of newly-formed air-tight pockets that disappear as the material is discharged therefrom, thereby eliminating any possibility of high pressure air being conveyed back to the material being directed into the new pockets.

Yet another object is the provision of apparatus capable of pumping fine particle materials for short distances without the addition of conveying air, and for longer dis} tances with the use of such air.

According to the prior art, materials in particle form are delivered into pneumatic conveying lines by means of barrel-type valves. These valves merely introduce the material into the lines but do not provide any positive pumping or delivery force. Barrel valves include pockets by means of which the particle materials are transferred into the pneumatic lines. Air under pressure is trapped in the pockets and tends to create blow-backs in the hoppers feeding the barrel-type valves. Attempts have been made to prevent this blow-back, but they have not been completely successful. The present method, and the apparatus for carrying out the method, practically eliminates the blow-back problem inherent in the apparatus of the prior art.

The method according to the present invention of introducing materials in particle form into high pressure pneumatic zones comprises directingparticle material into a newly-formed pocket, closing the filled pocket, moving the closed pocket to an entrance of a high pressure zone for discharge of the material from the pocket through the entrance into the zone, and reducing the size of the pocket while in communication with said entrance until said pocket disappears. This method has the advantage that no pockets travel from the pressure zone back to the pocket-filling area so that high pressure air cannot reach said area from said zone. Furthermore, the material is moved in closed pockets so that the sealing difiiculties of rotary feeders are not encountered.

Different forms of apparatus may be used for carrying out the present method. However, very satisfactory forms of pumping apparatus are described herein. While this pumping apparatus is particularly designed for directing material into a closed dispatch chamber or zone from which it is forced by air under pressure into a conveying pipe, it may be used merely as a pump for moving particle material along a pipe without the aid of conveying air.

According to the present method, particle material is directed into the inlet end of a newly-formed pocket. This may be done at the same time as the pocket is formed by closing the opposite ,end. After the .pocket is filled, its inlet end alsois closed or sealed so that atet the closed pocket may be moved to the entrance of a high pressure zone. When the pocket reaches the enf trance, its sealed end opposite the inlet end is opened to form an outlet communicating with the zone while the inlet end of the pocket is kept closed. This prevents any air from the zone from passing through the pocket; The size of the pocket is reduced progressively by moving the inlet end towards the zone to expel the material from the outlet end until the pocket disappears. The action of the pump may force particle material either into the dis patch chamber of a pneumatic conveying system or directly into a conveying pipe, or may force said material into and along a pipe communicating with the pump.

Pumping apparatus according to this invention comprises means successively forming pockets, means direct ing particle material into each pocket during the formation thereof, means sealing each filled pocket, means shifting each sealed pocket to an entrance of a pressure zone for discharge of the material from the pocket through the entrance into the zone, and means Op ning each pocket at the entrance for discharge of the particle material from said pocket and reducing the size of said pocket until the latter disappears.

Examples of this pumping apparatus are illustrated in the accompanying drawings, in which,

FIGURE 1 is a perspective view of the pumping apparatus, 1

FIGURE 2. is a side elevation of the apparatus, with part thereof broken away to show the drive means there- FIGURE 3 is a view of the apparatus with the near side of the casing broken away and showing the pumping means in side elevation,

FIGURE 4 is a section taken on the line 4-4 of FIGURE 3,

FIGURE 5 is a vertical section taken substantially on the line 5-5 of FIGURE 4, i

FIGURE 6 is a cross section taken on the line 6--6 of FIGURE 5,

FIGURE 7 is an enlarged section taken on the line 77 of FIGURE 3, showing tube-turning mechanism that has been omitted from FIGURE 3 for the sake of clarity,

FIGURE 8 is an elevation of the apparatus shown in FIGURE 7,

FIGURE 9 is a cross section taken on the line 9--9 of FIGURE 7,

FIGURES 10 to 13 diagrammatically illustrate the formation of the pockets in the pumping apparatus,

FIGURE 14 is a view similar to FIGURE 7 illustrating an alternative form of tube-turning mechanism,

FIGURE 15 is an elevation of the mechanism of FIGURE 14,

FIGURE 16 is a diagram illustrating the operation of the tube-turning mechanism of FIGURE 14,

FIGURE 17 is a front elevation of an alternative mounting -for the upper end of the pocket tube of the pumping apparatus, and

FIGURE 18 is a section taken on the line 18-48 of FIGURE 17.

Referring to the drawings, pumping apparatus 10 includes a casing 11 which houses the actual pump 12. While pump 12 may be in any desired position, such as vertical or horizontal, in the illustrated form of the invention, it is preferably in an inclined position, as shown in FIGURES 3 and 5. Pump 12 includes substantially parallel carriages 18 and 20, the former being stationary and the latter movable. The movable carriage preferably is adjustable towards and away from the stationary carriage, and it is so mounted that it is resiliently urged towardsthe latter.

Carriage 18 is fixedly mounted in casing 11 in any convenient manner, aiid it has parallel lower and upper shafts 24 and 25 at its opposite ends. One end 26 of shaft 24 projects through casing v11. Shaft 24 has a pair of sprockets 28 fixedly mounted thereon, while shaft 25 has a similar pair of sprockets 29 mounted thereon and in line with the first-mentioned sprockets. These sprockets are located near the sides of the carriage, and each set of sprockets 28 and 29 has a chain 32 extending there around. A plurality of pressure rollers 33 extend between these two chains 32 and are rotatably carried thereby. Each roller may be mounted on an axle 35 which extends between the chains, and rotatable bearings 36 are mounted on this shaft at the opposite ends of the roller. Carriage 18 is provided with a fiat track 37 extending longitudinally thereof in line with the bearings 36 at each end of rollers 33. During operation of the pump, chains 32 move in the direction of arrow 38, shown in FIGURE 3, and the tracks 37 are so located that bearings 36 ride on them during downward movement thereof.

Carriage 20 is constructed in the same manner and includes the same elements as carriage 18, that is, it includes lower and upper shafts 42 and 43 carrying pairs of sprockets 45 and 46 around which a pair of chains 47 extend. These chains carry axles 48 upon which are mounted rollers '49 and rotatable bearings 50. Chains 47 move in the direction of arrow 52 in FIGURE 3 during their downward movement and bearings 50 move along straight tracks 54 mounted on carriage 20. Shaft 42 has an end 56 projecting from casing 11 near the end 26 of shaft 24.

Carriage 20 may be mounted so that onlyits upper end is movable towards and away from carriage 18, but it is preferable to so mount it that both ends are movable relative to the stationary carriage 18. In this example, the lower end of carriage 20 is provided with downwardlyprojecting lugs 60 which are swingably connected by pins 61 to the ends of bars 62. Each bar 62 is therefore preferably slidably mounted in a bearing tube 63 which extends beneath and is carried by carriage 18. Each bar 62 and, consequently, the lower end of carriage 20, is resiliently biased towards carriage 18 A lug 64 is adjustably mounted on each bar and projects downwardly therefrom. Each lug is adjustably secured to its bar 62 by a set screw 65. A rod 66 which is. fixedly connected to tube 63 at 67 and extends parallel therewith, extends freely through lug 64, and has a nut 68 on the end thereof. A spring 69 is mounted on rod 66 between said nut and lug 64 and urges the lug away from the nut so as to urge the end of carriage 20 towards carriage 18. The upper part of lug 64 abuts against bearing tube 63 to limit the movement of carriage 20 towards carriage 18, and this limit may be changed by shifting this lug along the bar 62 on which it is mounted.

The upper end of carriage 20 is resiliently biased towards the upper end of carriage 18 by means of a pair of rods 70, one adjacent each side of the upper end of both carriages. Each rod 70 is fixedly connected to the upper end of carriage 18 at 7'1, and extends freely through a bearing 72 on the upper end of carriage 20. A spring 73 on each rod 70 tends to urge the upper end of carriage 20 away from carriage 18, while another spring 74 on the rod extending between bearing 72 and a nut 75 on the end of said rod tends to urge the upper end of carriage 20 towards carriage 18. The equilibrium position of the upper end of the movable carriage relative to the upper end of the stationary carriage established by the oppositelyacting springs 73 and 74 may be adjusted by turning out 75 on shaft 70.

Carriage chains 32 and 47 are driven by sprockets 80 and 81 mounted on the ends 26 and 56 of shafts 24 and 42, see FIGURE 2. The chain 82 extends under sprocket 80, around sprocket 81 on one side of sprocket 80, and around a drive sprocket 83 on the opposite side of the latter sprocket. A spring-loaded idler sprocket 8-4 is provided around which the chain 82 extends. Sprocket 83 is fixedly mounted on a shaft 86 which extends from a speed reduction unit 87 in casing 11 which, in turn, is operated by the drive shaft of a motor 88 in said casing. Movement of chain 82 causes sprockets and 81 to rotate in opposite directions, thereby rotating shafts 24 and 42 in opposite directions to move chains 32 and 47 in the direction of arrows 38 and 52, as shown in FIGURE 3. It will be noted that these chains are so arranged that rollers 33 and 49 move in pairs downwardly while the bearings 36 and 50 associated therewith travel over tracks 37 and 54.

A feed tube extends through pump 12 centrally thereof, that is, between carriages 18 and 20. This tube may be formed of any suitable flexible material, as long as it is impervious to gas. It is preferably moisture-proof, and it must be able to stand up to continuous flexing and abrasion. For example, it may be formed of a strong fabric which is impregnated with a long-lasting rubber-like compound, or it may be made of a reinforced plastic material such as urethane, or elastomer material having an artificial silk or other fabric reinforcement.

Tube 95- may be fixedly, rotatably or oscillatably mounted in pump 12 in any desired manner. It is preferablc, however, to mount it for slow, intermittent or oscillatory rotation around its longitudinal axis. FIG- URES 7, 8 and 9 illustrate the mechanism for imparting intermittent rotation to the tube. This mechanism has been omitted from FIGURES 3 and 5 for the sake of clarity. The upper end of tube 95 fits over a rotatable mounting sleeve 98 and is fixed thereto by a clamping ring 99. This sleeve extends upwardly through a housing 180 having a bottom 10d and a top 102. The sleeve rotatably extends through top 102 and has a shoulder 104 at its upper end which lies ever part of said top and rotably fits within an inlet pipe 105 which extends upuwardly through the top of casing 11. A sealing ring 106 is pro vided between shoulder 104 and pipe 105.

The lower end of tube 95 is clamped on to a rotatable mounting sleeve 110 by a clamping ring 111, said sleeve extending downwardly and rotatably fitting within a stationary outside sleeve 113. Inner sleeve 111 has an annular shoulder 115 projecting therefrom and fitting into a thrust bearing 116 carried by the upper end of outer sleeved13.

Housing 100 is fixedly mounted within casing 11 in any desired manner. Suitable means is provided within the housing for rotating upper sleeve 98. One way of doing this to to provide a worm gear 120 within the housing and surrounding and fixed to sleeve 98. This gear meshes with a worm 121 mounted on the end of a shaft 122 which is journalled in bearings 123 and 124 carried by the housing. A ratchet gear 126 is fixedly mounted on shaft 122, and an actuating arm 127 is swingably mounted at its upper end on said shaft and extends downwardly therefrom past ratchet gear 126. A pawl 129 is hingedly mounted on arm 127 close to and in engagement with gear 126. One end of this pawl is resiliently urged into engagement with the gear by a spring 130. A guard 132 is provided on the lower end of arm 127 and projects laterally therefrom. This arm projects downwardly slightly into the path of rollers 33 of carriage 18 so that as each roller moves past the arm, it swings the lower end of the latter enough to move pawl 129 to turn ratchet gear 126 a little. This rotates shaft 122, thereby causing the upper end of tube 95 to be turned by worm 121 and gear 120. This causes the whole tube to rotate around its axis. If desired, tube rotating mechanism may be located at the lower end of tube 95 along or along with that at the upper end of said tube.

For some purposes, pump 12 as described so far is sufiicient and will operate on its own. However, for most purposes, it is desirable to provide the pumping apparatus with a high pressure zone in the form of a dispatch chamber 135 below feed tube 95. It will be underassume stood, however, that the high pressure zone may be a conveying pipe through which air under pressure is moved. The chamber 135 is closed, excepting for an entrance 136 at its top into which outer sleeve 113 snugly fits. In other words, tube 95 discharges into the top of chamber 135. If it is necessary to space the chamber away from the pump, the entrance of said chamber may be in the form of a pipe extending thereto from feed tube.

The dispatch chamber 135 preferably tapers down at its lower end to a relatively small bottom 140 so that the lower section is in the form of an inverted truncated cone 141. A conveying pipe 145 extends downwardly through casing 11 and through top 146 of the dispatch chamber, and terminates at little above bottom 140. This pipe may be fixedly held in position or, as preferred, it is slidable through the chamber top 146 so that its entrance end 147 may be adjusted vertically relative to chamber bottom 140. Although it is not absolutely necessary, better results are obtained if a conical deflector 148 is provided on bottom 140 concentric with and projecting upwardly towards the entrance 147 of the conveying pipe. Raising and lowering the pipe changes the effective size of the entrance thereof since it is moved away from and towards the deflector 148.

As stated above, the pumping apparatus may be used without supplying air to the dispatch chamber. However, in most cases, it is necessary to supply air under pressure to chamber 135, and this may be done through pipe 150. This pipe enters into the chamber near the top thereof, and its end 151 is preferably directed towards the chamber entrance 136.

When the pumping apparatus is in operation, material in particle form, such as, for example, flour, is directed through feed pipe 105 into the upper end of tube 95.. It will be noted that rollers '33 and 49 work in pairs. As the rollers of each pair move around upper sprockets 29 and 46, they engage opposite sides of tube 95 near the top thereof and press said sides together to form a seal 160 therebetween. This, in efiect, forms a pocket 161 in the tube at the top thereof into which the flour is directed by pipe 105 and sleeve 98. As the pair of rollers move downwardly, pocket 161 lengthens and is being filled at the same time. As the rollers reach positions near the lower end of the tube as indicated by rollers 33a and 49a of FIGURE 5, rollers 33b and 49b of another pair are moved against the feed tube 95 to form a seal 165 at the top of pocket 161a. As soon as the upper seal 165 is formed, rollers 33a and 49!: start to move around lower sprockets 28 and 45, thereby moving away from each other. This opens the bottom of pocket 161a to permit the flour therein to drop through entrance 116 into dispatch chamber 135. Rollers 33b and 4% continue to move downwardly until pocket 161a disappears. It will be noted that rollers 33a and 49a do not separate until rollers 33b and 4% come together at the top of the pocket. Thus successive pockets are formed at the upper end of tube 95, and these pockets during and after being filled are worked downwardly along the tube until they disappear at the lower end thereof. The seal at the upper end of each pocket forms the lower seal of the next succeeding pocket.

FIGURES 10 to 13 diagrammatically illustrate the formation of a pocket in tube 95, the moving and seal-ing of the pocket, and the opening and discharge from the pocket until it disappears. In FIGURE 10, the pocket 16111 is formed by rollers 33a-49a which seal the lower end thereof. As these rollers move downwardly, said pocket moves in the same direction, as indicated in FIG- URE 11, until rollers 33b49b move in to seal the upper end thereof, as in FIGURE 12, then rollers 33a49a move .awayfrom the pocketto open its lower end to permit the particle material to be discharged therefrom, as in FIGURE 13. By the time rollers 33b49b reach their lowermost point, pocket 161a has disappeared.

As will be realized, the pairs of opposed rollers 33-49 6 rolling down the outside of tube produce considerable strain on the latter. The life of the tube is greatly increased by slowly or intermittently rotating it or oscillating it around its longitudinal axis during operation of the pumping apparatus. The pinch-off action imposed on the tube by the rollers takes place at continually changing circumferential locations thereon. It has been found that when the tube is rotated in one degree increments, or is oscillated, the pinch-off fatigue is only about V as much as it would be if it were not rotated.

Although rollers 3349 may be formed of any suitable material, it has been found that improved results are usually obtained if they are made of natural or artificial rubber composition, or other suitable material. With this arrangement, the surfaces of the rollers compress to a certain degree to conform to irregularities in the tube surface or to varying amounts of materials between the rollers. It has also been found necessary to lubricate the rollers at the surfaces thereof in order to reduce friction. This may be accomplished by forming the roller surfaces of a self-lubricating compound. For example, an elastomer compound covering with a self-lubricating ingredient such as molybdenum disulphide may be used. Alternatively, the roller surface material may he porous so that a suitable lubricant may be provided in the interior of the roller, in which case, the lubricant works through the porous material to provide the necessary lubrication. Another simple way is to provide oiling brushes in the paths of the two sets of rollers so that the lubricantis wiped on to saidrollers during movement thereof.

Pump 12 may not include a dispatch chamber when used for certain purposes. For example, tube 95 may discharge into a large pipe along which the particle material is moved by the pumping action. This would, of course, be practical only for movement over short distances.

It is also preferable to have tube 95 discharging directly into dispatch chamber 135, as illustrated in the drawings. However, tube 95 may discharge into a pipe of approximately the same diameter as the tube and which extends to the entrance of the discharge chamber. Furthermore, the tube may discharge directly into a pneumatic conveying pipe. In this case it would be provided with a seal such as is used between tube 95 and the dispatch chamber.

During operation of the pumping apparatus, the particle material is being continuously pumped into the high pressure zone or dispatch chamber. It is desirable to maintain a level of material in the latter chamber above the entrance end 147 of conveying pipe 145. This pumping action tends to increase the pressure in chamber so that fine materials may be moved for short distances through pipe as a result of the pumping action only, and Without the necessity of supplying any additional air to the chamber. However, if the particle material is relatively heavy or coarse, and/or it has to be moved for a considerable distance, it is necessary to supply air under pressure to the dispatch chamber through pipe This forces the material into and along pipe 145 so that it assists the normal pumping action. It is preferable for pipe 150 to enter the chamber near the top and have'its end 151 directed towards the entrance 136 of the dispatch chamber in order to help increase the speed of unloading of the disappearing pockets in tube 95.

As previously described, the upper pair of rollers 3349 always seal off tube 95 before the lower pair of these rollers separate to open the bottom of the pocket formed in the tube. This positively prevents any of the high pressure airof the dispatch chamber from blowing back through tube 95 to the upper end or entrance there of. Furthermore, as the pockets disappear by downward movement of rollers 33449, there is no communication between the dispatch chamber and the feed pipe 105 for flow of pressure air back to the feed entrance of the apparatus; 7

'Should the particle material tend to keep the upper sealing rollers of a pocket apart, pressure air from the dispatch chamber will force said material from between the rollers to allow them to press the sides of the tube together instantly to form a complete seal.

The spring loading of the upper end of carriage 20 reduces the strain on the pump. As each pair of rollers 33-49 move around the upper sprockets, they move against and press the sides of tube 95 together. The upper springs help to keep this actin from being too violent should the particle material be packed in the tube or if it is coarse and hard. Although not essential, it has been found advantageous to spring load the lower end of carriage 20 to enable the rollers to pass material which packs in the tube instead of rupturing the latter. This allows comparatively heavy granular or particle materials, suchas semolina, to be pumped through the apparatus. The coarser materials seem to have a tendency to jam between the rollers. The spring loading at the lower end of the carriage tends to relieve the strain on the apparatus when this takes place. This reduces the amount of power required for driving the apparatus, and it levels out or prevents power surges in the pump. This also reduces the abrading action on the tube by the sealing rollers. The spring loaded idler roller 84 on chain 82 permits the movement of shaft 42 relative to shaft 24 and the drive sprocket 83.

As this pumping apparatus operates without danger of blow-back through the feeding entrance thereof, the apparatus is able to operate in a dense phase wherein the particle material being moved has very little air entrained in it, and does not operate as a pneumatic system with air suspending the material particles in the conveying pipe. This makes it possible to operate at higher conveying pressures than are normally used with ordinary pneumatic systems. The amount of air for moving the particle material through conveying pipe 145 may be regulated by adjusting the entrance end 147 thereof upwardly or downwardly relative to the bottom of the dispatch chamber.

FIGURES 14 to 16 illustrate an alternative form of apparatus for rotating a tube 170 around its longitudinal axis. This tube is used for the same purpose as tube 95 described above. Tube 170 is formed with a seam or lap joint 171. The purpose of this mechanism is to oscillate the tube so that the seam or lap joint 171 is never in the pinched-off portion of the tube. FIGURE 16 diagrammatically shows rollers 33 and 49 engaging the tube on opposite sides thereof to form pinched-off portions 174 and 175 at opposite sides between said rollers. It has been found that if seam 171 is kept away from the portions 174 and 175 of the tube, the life of said tube is substantially prolonged.

Oscillatory apparatus 178 includes a gear or pinion 179 which is secured to the upper end of tube 170 in the same manner as gear 120 is secured to tube 95. Gear 179 is engaged by a rack 180, one end of which is connected by a link 181 to a crank arm 182. This crank arm is connected to a worm gear 183 which, in turn, meshes with a worm 184 on a shaft 185. A ratchet wheel 188 is fixedly mounted on an end of shaft 185 and is engaged by a spring-loaded pawl 189. This pawl is carried by an arm 190 swingably mounted on and hanging down from shaft 185. This arm has a plate 192 on its lower end which hands in the path of rollers 33 of carriage 18 of pump 12.

The rollers 33 during their travel engage plate 192 intermittently to swing arm 190, and this causes pawl 189 to rotate ratchet wheel 138. The ratchet wheel rotates shaft 185 and worm 184 causing worm gear 183 to rotate. This moved crank arm 182 around the axis of the worm gear, reciprocating rack 180. This rack being in engagement with gear 179 slowly oscillatesthe upper end of tube 170. The lengths of crank arm 182 and rack 180 are such that the tube is oscillated within an angle of less than 180. With this arrangement, if tube is placed so that the seam or lap 171 is initially located near but not in one of the tube portions 174 or 175, it never moves into either of said pinched-oil portions.

FIGURES l7 and 18 illustrate a spring mounting for a tube 200 which is similar to and used for the same purpose as tube 95. The upper end of tube 200 is connected to a plate 202 from which a feed pipe 203 projects upwardly. Plate 202 rests on a plurality of springs 205 that are carried by flanges 206 of supporting beams 207 extending transversely of the pump casing on opposite sides of the tube and supported by the casing in any convenient manner.

As the rollers, not shown, of the pump engage tube 200 and roll downwardly thercalong, said tube is subjected to great strain in a downward direction. If the tube is subjected to a sudden or impact load, springs 205 absorb at least some of the load and protect the tube from against excessive strain.

What 1 claim as my invention is:

1. Apparatus for pumping materials in particle form into a high pressure pneumatic zone without blow-back, comprising a flexible tube having an entrance at one end and an outlet at its other end, two pressure means, one a leading pressure means and the other a following pressure means, spaced apart lengthwise of the tube, cooperating to apply rolling pressure to opposite sides of the tube and forming a pocket therebetween, material supplying means directing particle material into said pocket, means moving said pressure means with the pocket therebetween conjointly away from such one end of said tube and towards its other end to shift the pocket to an entrance of a high pressure zone for discharge of the material from the pocket through the entrance into such zone, actuating means for said pressure means operable to move the following pressure means into tube-pressing position while the leading pressure means is in tube-pressing position and thereafter operable to move said leading pressure means out of tubepressing position for release of material from the pocket into the pressure zone, and means connected to said tube for slowly moving it around the longitudinal axis thereof to cause said pressure means to engage different portions of said tube during movement thereof.

2. Apparatus for pumping materials in particle form into a high pressure pneumatic zone without blow-back, comprising a flexible tube having an entrance at one end and an outlet at its other end, two pressure means, one a leading pressure means and the other a following pressure means, spaced apart lengthwise of the tube, cooperating to apply rolling pressure to opposite sides of the tube and forming a pocket therebetween, material supplying means directing particle material into said pocket, means moving said pressure means with the pocket therebetween conjointly away from such one end of said tube and towards its other end to shift the pocket to an entrance of a high pressure zone for discharge of the material from the pocket through the entrance into such zone, actuating means for said pressure means operable to move the following pressure means i-nto tube-pressing position while the leading pressure means is in tube-pressing position and thereafter operable to move said leading pressure means out of tube-pressing position for release of material from the pocket into the pressure zone, and means connected to said tube for slowly rotating it around the longitudinal axis thereof to cause said pressure means to engage different portions of said tube during rotation thereof.

3. Apparatus for pumping materials in particle form into a high pressure pneumatic zone without blow-back, comprising a flexible tube having an entrance at one end and an outlet at its other end, two pressure means, one a leading pressure means and the other a following pressure means, spaced apart lengthwise of the tube, cooperating to apply rolling pressure to opposite sides of the tube and forming a pocket therebetween, material supplying means directiong particle material into said pocket, means moving said pressure means with the pocket therebetween conjointly away from such one end of said tube and towards its other end to shift the pocket to an entrance of a high pressure zone for discharge of the material from the pocket through the entrance into such zone, actuating means for said pressure means operable to move the fol lowing pressure means into tube-pressing position while the leading pressure means is in tube-p-ressing position and thereafter operable to move said leading pressure means out of tube-pressing position for release of material from the pocket into the pressure zone, and means connected to said tube for slowly oscillating it around the longitudinal axis thereof to cause said pressure means to engage difierent portions of said tube during oscillation thereof.

4. Apparatus for pumping materials in particle form into a high pressure pneumatic zone Without blow-back, comprising a flexible tube having an entrance at one end and an outlet at its other end, two pressure means, one a leading pressure means and the other a following pressure means, spaced apart lengthwise of the tube, cooperating to apply rolling pressure to opposite sides of the tube and forming a pocket therebetween, material supplying means directing particle material into said pocket, means moving said pressure means with the pocket therebetween conjointly away from such one end of said tube and towards its other end to shift the pocket to an entrance of a high pressure zone for discharge of the material from the pocket through the entrance into such Zone, actuating means for said pressure means operable to move the following pressure means into tube-pressing position while the leading pressure means is in tubepressing position and thereafter operable to move said leading pressure means out of tube-pressing position for release of material from the pocket into the pressure zone, and means resiliently supporting the entrance end of said tube to absorb loads applied to said tube lengthwise thereof away from said supporting means.

5. Apparatus for pumping materials in particle form into a high pressure pneumatic zone without blow-back, comprising a flexible tube having an entrance at one end and an outlet at its other end, two pressure means of resilient material, one a leading pressure means and the other a following pressure means, spaced apart lengthwise of the tube, cooperating to apply rolling pressure to opposite sides of the tube, conforming to irregularities in the tube surface and forming a pocket therebetween, material supplying means directing particle material into said pocket, means moving said pressure means with the pocket therebetween conjointly away from such one end of said tube and towards its other end to shift the pocket to an entrance of a high pressure zone for discharge of the material from the pocket through the entrance into such zone, and actuating means for said pressure means operable to move the following pressure means into tubepressing position while the leading pressure means is in tube-pressing position and thereafter operable to move said leading pressure means out of tube-pressing position for release of material from the pocket into the pressure zone.

6. In apparatus for pumping materials in particle form, a pair of substantially parallel carriages, means resiliently urging the carriages relatively toward each other, a gasimpervious flexible tube extending between said carriages and having a feed entrance at one end and an outlet at its other end, a plurality of rollers mounted on each carriage for rotation about axes extending transversely of the length of said tube, and means for moving said rollers in opposed positions on their respective carriages through endless paths arranged to bring opposed rollers of said pair of carriages into tube-sealing engagement with the tube near the tube entrance, moving opposed rollers conjointly along said tube and separating such opposed rollers from each other to disengage the tube near the tube outlet end, each of said rollers being so spaced along said moving means with respect to the next following roller that a following roller engages the tube before the roller ahead disengages it, and opposed rollers engaging said tube to press opposite sides thereof together to create a seal for pockets formed in said tube on opposite sides of said opposed rollers longitudinally of said tube, whereby particle material directed into the tube inlet is moved along the tube in sealed pockets and discharged from the tube outlet as the pockets disappear at such outlet.

7. Pumping apparatus as claimed in claim 6, in which one end of one carriage is mounted on a pivot mounted near the adjacent end of the other carriage, and the resiliently urging means includes spring means at the opposite end of such one carriage resiliently urging the latter end towards the adjacent end of such other carriage.

8. Pumping apparatus as claimed in claim 7, including means for adjusting the carriage pivot towards and away from the adjacent end of such other carriage.

References Cited in the file of this patent UNITED STATES PATENTS 968,599 Du Pont Aug. 30, 1910 FOREIGN PATENTS 360,943 Great Britain Nov. 9, 1931 689,486 Great Britain Mar. 25, 1953 926,775 Germany Apr. 25, 1955 949,998 Germany Sept. 27, 1956 

